Captivating Crew and Mass Mutiny play on borrowing your opponents' creatures, which decreases their available blockers and gives you most of the benefits those creatures bring with them
Collector Boosters / Booster Display The vault is open
Learning From the Past Funny enough, this whole rules debacle could be solved easily by issuing an errata to Selvala, writing at the end of her ability: Activate this ability only any time you could cast an instant. This prevents the ability from being activated during the spellcasting process, as you cant cast instants during the process of casting another spell
They're Jaya Ballard's goggles
Wily Bandar: mid game versatility with the indestructible clause
Put the rest on the bottom of your library in a random order." On top of that, it also costs one less mana to cast for each artifact you control, which means it could be as low as two mana if you've got enough artifacts in play